The present invention relates to plate-like cutting inserts, intended for chip removing machining of metallic materials, the inserts having a central hole for receiving part of a clamp. Such indexable inserts normally have cutting tip angles below 80° and are usually intended for different types of copying. On the market, there is now a plurality of different types of insert holders, which are especially adapted for such indexable inserts, such as rhombic, rhomboid or isosceles triangular indexable inserts. The material used to make such indexable inserts is normally sintered cemented carbide or ceramics.
A frequently used type of indexable insert is provided with a so-called wiper geometry outside in each active cutting corner. The meaning of this is a radius-modified corner geometry, with the corner radius in the cutting corner being composed of a plurality of small radii adjacent each other, with each radius portion adjoining the next radius portion having another radius size. With this type of geometry, it has become possible to increase the feeding of the cutting insert significantly at the same time as a desired good surface finish of the machined workpiece can be attained. Upon the use of such cutting inserts having a wiper geometry, the cutting insert is not clamped by the usual lever holders, e.g., of the type shown and disclosed in U.S. Pat. No. 3,314,126. Upon use of a wiper insert, it is now desirable to employ a holder system, which upon clamping of the cutting insert, applies not only an inward-drawing force but simultaneously also a downward-pressing force. This represents in itself a certain limitation as for the choice of geometries for the upper chip side of the cutting insert.